Introduction to Hydropower

Hydroelectric power, or hydroelectricity, is basically electrical energy that has been generated using natural forces such as gravity or flowing water. It's usually produced by dams, because dams can store and direct large volumes of water. Hydroelectric power is becoming increasingly popular.

Dams can generate electricity because they contain special mechanisms designed to take the energy in flowing water and turn it into electrical power. A power source is used to spin a turbine—basically a propeller—which in turn spins a metal shaft, forming the equivalent of an electrical generator that produces and stores electricity. The power source, in the case of hydropower, is water itself. When water moves a turbine, the turbine spins, and electromagnets in the turbine generate an electric current in the stationary coils of wire inside them.

Great Green Alternative

Hydroelectric power is the most popular "green" energy source for several reasons. First, the cost of the fuel needed to generate hydropower is miniscule because the process doesn't use any of the more common polluting fuels, such as oil, coal, or natural gas. This means that, unlike other power plants, hydroelectric plants don't produce carbon dioxide. A hydroelectric plant is also a lot cheaper to operate because it can be fully automated, saving labor costs, and because its facilities don't need to be repaired frequently. Many hydroelectric plants have been in use for at least 50 years, and they are still running smoothly.

A "pumped-storage" plant usually consists of a dam combined with a sluice system that allows water to move between a higher-elevation reservoir behind the dam and a lower-elevation outlet in front of the dam. During times of peak energy usage, the water is allowed to flow from the higher elevation to the lower elevation. Along the way it spins a turbine, using the force of gravity to generate electricity. When the demand for electricity falls—during the night, for instance—excess power is used to pump water from the lower elevation back up to the reservoir. The reservoir serves as a sort of massive battery that can be tapped when the demand for electricity increases again.

Hydropower on the Farm

If you are thinking of setting up a hydroelectric power system on a farm or ranch, you'll need a source of flowing water, an intake unit, a pipeline, and a powerhouse with a turbine. The stream that serves as water source should separate from a larger watercourse, pass through the intake unit and the pipeline, run into the powerhouse to turn the turbine, and then merge with the watercourse once again.

Hydropower at Home

Many people have moving water on their land—water that could be used to produce hydropower. To generate hydroelectricity, property owners need a water source that loses at least three feet of elevation, a large pipeline, and a water turbine. Water turbines come in two types. Impulse turbines work by spraying jets of water onto a wheel, while reaction turbines use a propeller inside the pipe to generate power.

Hydropower in the Classroom

Hydro Power: A science project that displays the power of water pressure.
Generate Your Own Hydropower: A lesson plan that demonstrates how water can be used to generate electricity.
Water Energy: Resources for teaching about hydropower.
Hydropower (Water Power): A list of links to experiments and background information on hydropower.
Hydropower: A U.S. government site which explains hydropower to kids.